Active vibration stabilizer and isolator

Claim 1

An active vibration isolator for disposition between a support and a payload, said isolator comprising: a cylinder having an axis and being disposed for supporting said payload on one end thereof; a piston disposed for axial movement in said cylinder, said piston defining in said cylinder a first chamber proximate said one end and a second chamber proximate the other end; a piston rod extending through the other end of said cylinder between said piston and said support; ball joint means connecting said piston rod to said piston and to said support for permitting relative movement between said piston and support in a plane generally perpendicular to said axis; means communicating with said cylinder for conducting fluid to an from said first chamber; means in said cylinder at said one end for sensing changes in pressure of the fluid in said first chamber caused by relative motion between said piston and cylinder and for generating signals representative of said changes in pressure; and means responsive to said signals and operatively connected to said conducting means for maintaining a predetermined substantially constant pressure in said first chamber.